Idiom: go on

'Go on' has several different meanings. One meaning is 'talk too much'. If you go on about something, you talk about it a lot - because you are excited, enthusiastic or upset about it - although other people are not very interested.

When I was a child, I used to go on about video games. These days, I try not to go on too much about my interests.

This expression has a rather negative meaning.
'My friend was talking about his problems.'
'My friend was going on about his problems.'
In this second sentence, you are not very interested in their problems. You think they should talk less about their problems.

'go on and on' is even stronger. If your friend was going on and on about his problems, he was really talking for a long time!

Do you sometimes go on a bit? What do you go on about?